From a96071f9d3c0c0219226951c3263878b1638f26a Mon Sep 17 00:00:00 2001
From: Benau <Benau@users.noreply.github.com>
Date: Mon, 27 May 2019 12:17:08 +0800
Subject: [PATCH] Make android callback thread safe

---
 .../source/Irrlicht/CIrrDeviceAndroid.cpp     | 10 ++++---
 src/guiengine/engine.cpp                      | 30 +++++++++++++++++++
 src/guiengine/engine.hpp                      |  5 ++++
 src/guiengine/widgets/text_box_widget.cpp     | 16 +++++++---
 4 files changed, 53 insertions(+), 8 deletions(-)

diff --git a/lib/irrlicht/source/Irrlicht/CIrrDeviceAndroid.cpp b/lib/irrlicht/source/Irrlicht/CIrrDeviceAndroid.cpp
index b22e4c7f6..e3e0029b9 100644
--- a/lib/irrlicht/source/Irrlicht/CIrrDeviceAndroid.cpp
+++ b/lib/irrlicht/source/Irrlicht/CIrrDeviceAndroid.cpp
@@ -9,6 +9,7 @@
 #ifdef _IRR_COMPILE_WITH_ANDROID_DEVICE_
 
 #include <assert.h>
+#include <atomic>
 #include <vector>
 #include "os.h"
 #include "CContextEGL.h"
@@ -43,7 +44,7 @@ ANDROID_SAVE_CHARS_CALLBACK(ANDROID_PACKAGE_CALLBACK_NAME)
 
 // Call when android keyboard is opened or close, and save its height for
 // moving screen
-int g_keyboard_height = 0;
+std::atomic<int> g_keyboard_height(0);
 
 #define MAKE_ANDROID_SAVE_KBD_HEIGHT_CALLBACK(x) JNIEXPORT void JNICALL Java_ ## x##_SuperTuxKartActivity_saveKeyboardHeight(JNIEnv* env, jobject this_obj, jint height)
 #define ANDROID_SAVE_KBD_HEIGHT_CALLBACK(PKG_NAME) MAKE_ANDROID_SAVE_KBD_HEIGHT_CALLBACK(PKG_NAME)
@@ -51,7 +52,7 @@ int g_keyboard_height = 0;
 extern "C"
 ANDROID_SAVE_KBD_HEIGHT_CALLBACK(ANDROID_PACKAGE_CALLBACK_NAME)
 {
-    g_keyboard_height = (int)height;
+    g_keyboard_height.store((int)height);
 }
 
 namespace irr
@@ -227,8 +228,9 @@ void CIrrDeviceAndroid::printConfig()
 
 u32 CIrrDeviceAndroid::getOnScreenKeyboardHeight() const
 {
-    if (g_keyboard_height > 0)
-        return g_keyboard_height;
+    int height = g_keyboard_height.load();
+    if (height > 0)
+        return height;
     return 0;
 }
 
diff --git a/src/guiengine/engine.cpp b/src/guiengine/engine.cpp
index 7d93f1f1e..5a3285a7b 100644
--- a/src/guiengine/engine.cpp
+++ b/src/guiengine/engine.cpp
@@ -685,9 +685,11 @@ namespace GUIEngine
 #include "states_screens/race_gui_base.hpp"
 #include "utils/debug.hpp"
 
+#include <algorithm>
 #include <iostream>
 #include <assert.h>
 #include <irrlicht.h>
+#include <mutex>
 
 using namespace irr::gui;
 using namespace irr::video;
@@ -716,6 +718,10 @@ namespace GUIEngine
         int large_font_height;
         int small_font_height;
         int title_font_height;
+#ifdef ANDROID
+        std::mutex m_gui_functions_mutex;
+        std::vector<std::function<void()> > m_gui_functions;
+#endif
     }
     using namespace Private;
 
@@ -1144,6 +1150,15 @@ namespace GUIEngine
         assert(g_skin->getReferenceCount() == 1);
     }   // reloadSkin
 
+    // -----------------------------------------------------------------------
+    void addGUIFunctionBeforeRendering(std::function<void()> func)
+    {
+#ifdef ANDROID
+        std::lock_guard<std::mutex> lock(m_gui_functions_mutex);
+        m_gui_functions.push_back(func);
+#endif
+    }   // addGUIFunctionBeforeRendering
+
     // -----------------------------------------------------------------------
     /** \brief called on every frame to trigger the rendering of the GUI.
      *  \param elapsed_time Time since last rendering calls (in seconds).
@@ -1158,6 +1173,21 @@ namespace GUIEngine
         // Not yet initialized, or already cleaned up
         if (g_skin == NULL) return;
 
+#ifdef ANDROID
+        // Run all GUI functions first (if any)
+        std::unique_lock<std::mutex> ul(m_gui_functions_mutex);
+        if (!m_gui_functions.empty())
+        {
+            std::vector<std::function<void()> > functions;
+            std::swap(functions, m_gui_functions);
+            ul.unlock();
+            for (auto& f : functions)
+                f();
+        }
+        else
+            ul.unlock();
+#endif
+
         // ---- menu drawing
 
         // draw background image and sections
diff --git a/src/guiengine/engine.hpp b/src/guiengine/engine.hpp
index c49dbf107..54e801c2c 100644
--- a/src/guiengine/engine.hpp
+++ b/src/guiengine/engine.hpp
@@ -34,6 +34,7 @@ namespace irr
     namespace video { class IVideoDriver; class ITexture;        }
 }
 
+#include <functional>
 #include <string>
 
 #include "utils/constants.hpp"
@@ -248,6 +249,10 @@ namespace GUIEngine
       */
     void reloadSkin();
 
+    /**
+      * \brief Add gui-related function before rendering GUI (from other thread)
+      */
+    void addGUIFunctionBeforeRendering(std::function<void()> func);
 }
 
 #endif
diff --git a/src/guiengine/widgets/text_box_widget.cpp b/src/guiengine/widgets/text_box_widget.cpp
index 42dd57353..36e1fd6fc 100644
--- a/src/guiengine/widgets/text_box_widget.cpp
+++ b/src/guiengine/widgets/text_box_widget.cpp
@@ -246,8 +246,7 @@ EventPropagation TextBoxWidget::leftPressed (const int playerID)
 extern "C"
 ANDROID_EDITTEXT_CALLBACK(ANDROID_PACKAGE_CALLBACK_NAME)
 {
-    TextBoxWidget* tb = dynamic_cast<TextBoxWidget*>(getFocusForPlayer(0));
-    if (!tb || (int)widget_id != tb->getID() || text == NULL)
+    if (text == NULL)
         return;
 
     const char* utf8_text = env->GetStringUTFChars(text, NULL);
@@ -262,8 +261,17 @@ ANDROID_EDITTEXT_CALLBACK(ANDROID_PACKAGE_CALLBACK_NAME)
     utf32line.push_back(0);
 
     core::stringw to_editbox(&utf32line[0]);
-    tb->getIrrlichtElement<MyCGUIEditBox>()->fromAndroidEditText(
-        to_editbox, start, end, composing_start, composing_end);
     env->ReleaseStringUTFChars(text, utf8_text);
+
+    GUIEngine::addGUIFunctionBeforeRendering([widget_id, to_editbox, start,
+        end, composing_start, composing_end]()
+        {
+            TextBoxWidget* tb =
+                dynamic_cast<TextBoxWidget*>(getFocusForPlayer(0));
+            if (!tb || (int)widget_id != tb->getID())
+                return;
+            tb->getIrrlichtElement<MyCGUIEditBox>()->fromAndroidEditText(
+                to_editbox, start, end, composing_start, composing_end);
+        });
 }
 #endif